Cooperation through Competition-Dynamics and Microeconomics of a Minimal Nutrient Trade System in Arbuscular Mycorrhizal Symbiosis.
Cooperation through Competition-Dynamics and Microeconomics of a Minimal Nutrient Trade System in Arbuscular Mycorrhizal Symbiosis.
复制标题
DOI：
10.3389/fpls.2016.00912
复制
发表时间：
2016
影响因子：
5.6
通讯作者：
Dreyer I
中科院分区：
文献类型：
--
作者：
Schott S;Valdebenito B;Bustos D;Gomez-Porras JL;Sharma T;Dreyer I
在丛枝菌根 (AM) 共生中，真菌和植物交换营养物质（例如糖和磷酸盐）以实现互惠互利。到目前为止，还不清楚这种营养交换系统是如何运作的。在这里，我们使用计算细胞生物学来模拟质子泵和质子耦合转运蛋白网络的动力学，这些网络在 AM 形成过程中上调。我们证明这个最小的网络足以准确、真实地描述养分贸易系统。通过应用微观经济学的基本原理，我们将跨膜养分运输的生物物理学与有机体相互作用的生态学联系起来，并直接解释植物和 AM 真菌之间关系的宏观情景。这项计算细胞生物学研究可以对养分交换的机制和调节提出深远的假设，并提出植物和真菌之间的“合作”实际上可能是两者在微小的枝周空间中争夺相同资源的结果。这里提出的最小模型可以作为评估未来更复杂的 AM 营养交换模型性能的基准。作为实现这一目标的第一步，我们在模型中加入了 SWEET 糖转运蛋白，并表明它们与质子耦合糖转运蛋白的共存会导致植物质膜上的无效碳循环，这表明同一底物的两个不同途径不应同时处于活动状态。
In arbuscular mycorrhizal (AM) symbiosis, fungi and plants exchange nutrients (sugars and phosphate, for instance) for reciprocal benefit. Until now it is not clear how this nutrient exchange system works. Here, we used computational cell biology to simulate the dynamics of a network of proton pumps and proton-coupled transporters that are upregulated during AM formation. We show that this minimal network is sufficient to describe accurately and realistically the nutrient trade system. By applying basic principles of microeconomics, we link the biophysics of transmembrane nutrient transport with the ecology of organismic interactions and straightforwardly explain macroscopic scenarios of the relations between plant and AM fungus. This computational cell biology study allows drawing far reaching hypotheses about the mechanism and the regulation of nutrient exchange and proposes that the “cooperation” between plant and fungus can be in fact the result of a competition between both for the same resources in the tiny periarbuscular space. The minimal model presented here may serve as benchmark to evaluate in future the performance of more complex models of AM nutrient exchange. As a first step toward this goal, we included SWEET sugar transporters in the model and show that their co-occurrence with proton-coupled sugar transporters results in a futile carbon cycle at the plant plasma membrane proposing that two different pathways for the same substrate should not be active at the same time.